Education Department officials said they are investigating the incident. Police sources said the student was treated with CPR and the Heimlich maneuver.

City schools boss Carmen Fariña said her heart goes out to the stricken mom.

"As a parent and a grandparent, I can't imagine what she's going though," saidFariña.

"At this point, I wouldn’t do anything but hug her and say to her, 'Look, we understand what you’re going through, and then what can we do to make it better?' But you can’t make that better– you can’t bring a child back."